Digest for sci.electronics.repair@googlegroups.com - 12 updates in 3 topics

rachana.balakumar@gmail.com: Feb 19 08:42AM -0800

> List of Solutions Manuals and Test Banks
> ________________________________________
 
> Hi i need the solution manual for
Solution manual Mass and Heat Transfer : Analysis of Mass Contactors and Heat Exchangers (T. W. Fraser Russell, Anne S. Robinson, Norman J. Wagne
"(PeteCresswell)" <x@y.Invalid>: Feb 18 03:47PM -0500

Per KenO:
>Inherited an electronics unit that has severe contact corrosion due to bad alkaline batteries.
 
>Appreciate any suggestions how to restore these contacts to working condition.
 
White vinegar applied with a Q-Tip worked for me the one time I had a similar
situation.
--
Pete Cresswell
John Robertson <spam@flippers.com>: Feb 18 03:46PM -0800

On 2018/02/17 12:06 PM, Reinhard Zwirner wrote:
 
> As has been suggested in a previous thread: (concentrated) white vinegar.
 
> HTH
 
> Reinhard
 
Actually the EverReady battery engineer I spoke to back in the late 80s
recommended white vinegar:water with a 50:50 ratio, not pure or
concentrated white vinegar.
 
A weak acid to neutralize a weak base.
 
And as Peter W. so correctly pointed out, the common zinc/carbon battery
leaks a mild acid and so you use baking soda (a mild base).
 
So be sure to identify the type of battery before attempting corrective
measures.
 
John :-#)#
 
--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
Reinhard Zwirner <reinhard.zwirner@t-online.de>: Feb 19 03:23PM +0100

John Robertson schrieb:
> On 2018/02/17 12:06 PM, Reinhard Zwirner wrote:
 
[...]
 
> Actually the EverReady battery engineer I spoke to back in the late
> 80s recommended white vinegar:water with a 50:50 ratio, not pure or
> concentrated white vinegar.
 
My experience: concentrated white vinegar achieves best results. But
YMMV ...
 
[...]
> So be sure to identify the type of battery before attempting
> corrective measures.
 
FACK!
 
Best regards
 
Reinhard
KenO <kenitholson@yahoo.com>: Feb 19 07:37AM -0800

Thanks everyone for your suggestions!!!
 
Will try to combine any questions.
 
"...identify the type of battery before attempting corrective
measures" Unfortunately the person I received the electronic device from removed the batteries and does not remember if the batteries were zinc/carbon or alkaline.
 
Question: Can baking soda if used on the residue left by alkaline batteries cause additional damage?
Terry Schwartz <tschw10117@aol.com>: Feb 19 07:44AM -0800

Your initial post said alkaline batteries.
 
 
On Monday, February 19, 2018 at 9:37:37 AM UTC-6, KenO wrote:
peter wieck <peterwieck9@gmail.com>: Feb 19 07:48AM -0800

On Monday, February 19, 2018 at 9:37:37 AM UTC-6, KenO wrote:
 
> Question: Can baking soda if used on the residue left by alkaline batteries cause additional damage?
 
For the most part, none of the items suggested here will cause damage, even if not the "ideal" solution. Vinegar at household strength is quite mild and will not cause horrendous damage to much of anything if used judiciously. Baking Soda is similarly fairly inert. Both have indirect virtues inasmuch as they are effective anti-odorants as well as being reasonably effective germicides and fungicides. The key with using any water-based cleaning methods on electronics is the complete removal of same at the end of the process.
 
Peter Wieck
Melrose Park, PA
KenO <kenitholson@yahoo.com>: Feb 19 07:52AM -0800

"white vinegar" search
 
checked the top Google results but did not find any mention to either dilute with water or use full strength.
https://hallmark.custhelp.com/app/answers/detail/a_id/3918/~/how-to-clean-a-battery-compartment-containing-corroded-alkaline-batteries.
https://www.bobvila.com/articles/how-to-clean-battery-corrosion/
http://www.radioworld.com/columns-and-views/0004/vinegar-is-your friend/323304
 
John and Reinhard do you have any references for your recommendations?
KenO <kenitholson@yahoo.com>: Feb 19 08:00AM -0800

John-Del,
 
"The first thing to try when removing battery snot is plain old water. If the plating is gone, you'll either have to replate or replace the contacts for reliable contact"
 
I hope the plating is OK
 
Will plain water cause additional damage if the plating is damaged?
 
Ian,
 
"Dry corrosion/residue is best removed mechanically - once its clean enough
for reliable contact, give it a squirt of silicone spray"
 
What do you suggest to mechanically remove the dry residue? It seems to be adherent to the contact surface (not loose and flakey).
Fox's Mercantile <jdangus@att.net>: Feb 19 10:08AM -0600

On 2/19/18 9:37 AM, KenO wrote:
> Unfortunately the person I received the electronic device from removed
> the batteries and does not remember if the batteries were zinc/carbon
> or alkaline.
 
Simple really. Alkaline batteries leave what looks like white fuzzy
crystals. Some times with bluish green tint.
 
Zinc Carbon batteries leave what looks like rusty brown sludge. That is
also spread about more and not confined to just the terminals.
 
 
--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com
Jeff Liebermann <jeffl@cruzio.com>: Feb 19 08:36AM -0800

On Sat, 17 Feb 2018 10:05:32 -0800 (PST), KenO <kenitholson@yahoo.com>
wrote:
 
>Appreciate any suggestions how to restore these contacts to working condition.
>Thanks
>Ken
 
Replace them with shiny new contacts:
<https://www.ebay.com/sch/i.html?_nkw=battery+spring+contact>
 
If you plan to keep your "electronics unit", consider replacing the
alkaline cells with rechargeable NiMH LSD (low self discharge) cells
such as Eneloop. These types of cells can also leak, but in my
experience much less often.
<https://www.knivesandtools.com/en/ct/low-self-discharge-nimh-batteries.htm>
 
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
"~misfit~" <shaun.at.pukekohe@gmail.com>: Feb 19 04:41PM +1300

Once upon a time on usenet Jeff Liebermann wrote:
> the area from the outside. The only way to get the crud out is to
> tear it apart.
> http://www.learnbydestroying.com/jeffl/pics/repair/HP%20Envy%20m6%20clogged%20fan/slides/clogged_fan.html
 
The HP envy that I have likewise must be stripped down to where the top and
bottom shells are apart to clean the fan. This is what the fins looked like
when I finally got there:
http://test.internet-webmaster.de/upload/1519009591.jpg
I was fully intending to cut a hole in the bottom case (and make a hinged
door with tape) so I could access the fan / fins for the frequent cleaning
it will require but the fan lifts out *upwards* and is half under the
keyboard.
 
(In that picture the heatpipe that you can see is the one from the GPU
that's already been past a smaller set of fins [out-of-shot to the right].
Behind that are the two heatpies that come directly from the 3GHz quad core
i7 CPUs heat collector.)
 
> The bottom cover comes off exposing the entire heat pipe assembly,
> which is then easily cleaned. Too bad Dell (or Foxcom) designed it
> into a crappy machine (Inspiron 1525) with miserable BGA soldering.
 
I've not seen setups like that on recent machines. IMO manufacturers are
using 'heatsink clog' combined with difficulty of disassembly / reassembly
(with fragile plastic clips and ribbon cables) as a form of built-in
obsolescence. After all CPUs and SSDs aren't becoming obsolete /
underpowered as quickly as they once did...
 
> More later. Gotta run.
 
Cheers,
--
Shaun.
 
"Humans will have advanced a long, long way when religious belief has a cozy
little classification in the DSM*."
David Melville (in r.a.s.f1)
(*Diagnostic and Statistical Manual of Mental Disorders)
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Digest for sci.electronics.repair@googlegroups.com - 15 updates in 4 topics

micmouse10@aol.com: Feb 18 06:31AM -0800

Did you ever get this fixed??
micmouse10@aol.com: Feb 18 06:31AM -0800

DId you ever get this fixed?
ggherold@gmail.com: Feb 17 10:11AM -0800

On Friday, January 26, 2018 at 2:45:57 PM UTC-5, BenAnd wrote:
 
> What material bit for either 1/4" OR 1/8" shank hand drill motor or
> Dremel is best to use ?
 
> I have many of these to do.
 
Can you just re-cut the end?
Maybe a step drill bit, or a conical bit.
(A dremel sounds a bit wimpy for the job, unless it's thin walled
SS.)
 
George H.
MOP CAP <email@domain.com>: Feb 17 01:55PM -0800

I may not understand exactly what you mean. When plumbers and
electrician cut pipe or conduit they use a conical pipe reamer or for
lighter pipe a flat vee shaped one.
CP
Ralph Mowery <rmowery28146@earthlink.net>: Feb 17 05:06PM -0500

In article <5bcf8620-15e5-4969-8a62-9d196751cc9c@googlegroups.com>,
ggherold@gmail.com says...
> (A dremel sounds a bit wimpy for the job, unless it's thin walled
> SS.)
 
> George H.
 
Did anyone mention a tapered reamer ? The pipe threading machines
usually have them built in.
KenO <kenitholson@yahoo.com>: Feb 17 09:09AM -0800

Hi
 
Update since posting.
 
Did not get an immediate response so went to Youtube and searched using diagnosis repair Delta Electronics DPS-310CD ATX power supplies got ~ 197 results. Then started watching the videos.
 
One thing mentioned was to wait a while for caps to discharge so decided to take plenty of time and waited until this morning to test.
 
First thing I did was to recheck all the caps for bulges or leaks. Found none. Also rechecked for burn marks on pc board and components. Also found none. Still was unable to identify anything that looked like a fuse. Would be nice to find a schematic for DPS-310CD. Have done some searching but to date have not found one.
 
Then decided to try starting. Followed the connect green and black wires of main power connector http://www.instructables.com/id/Take-a-Look-Inside-a-ATX-power-supply-for-computer/ to start and was surprised that green lite on PSU came on and got readings of 11.89V for yellow and black, and 5.15V for red and black wires of a parallel HDD connector.
 
Am wondering if 11.89V for HDDs is too low? I do not have a scope to check the wave form but the readings were stable on my meter.
KenO <kenitholson@yahoo.com>: Feb 17 09:12AM -0800

Update cont.
 
Forgot to mention the Fan came on when started..
KenO <kenitholson@yahoo.com>: Feb 17 09:15AM -0800

Eric,
 
"Recently I had a power supply in a computer that was going bad. It
wouldn't work properly until it was warm. I replaced it but before I
did I found that directing the warm air from a blow dryer through the
fan and warming the power supply would allow it to turn on. Once on it
would stay on."
 
Any ideas why it needed to be warm?
KenO <kenitholson@yahoo.com>: Feb 17 09:19AM -0800

Ralph,
 
"I had a piece of equipment with a power supply that had lots of
capacitors in it. I found the bad ones by directing the hot air from my
hot air rework station at them."
 
That was what I was expecting to find!
etpm@whidbey.com: Feb 17 10:50AM -0800

On Sat, 17 Feb 2018 09:15:02 -0800 (PST), KenO <kenitholson@yahoo.com>
wrote:
 
>fan and warming the power supply would allow it to turn on. Once on it
>would stay on."
 
>Any ideas why it needed to be warm?
I was told by some folks here who know about this stuff that failing
electrolytic capacitors will sometimes work better once warm. They do
not need to be bulging to be bad or going bad.
Eric
Ralph Mowery <rmowery28146@earthlink.net>: Feb 17 04:51PM -0500

In article <f22ea9c5-13ac-4e5c-87a5-839f6e2915aa@googlegroups.com>,
kenitholson@yahoo.com says...
 
> One thing mentioned was to wait a while for caps to discharge so decided to take plenty of time and waited until this morning to test.
 
> First thing I did was to recheck all the caps for bulges or leaks. Found none. Also rechecked for burn marks on pc board and components. Also found none. Still was unable to identify anything that looked like a fuse. Would be nice to find a schematic for DPS-310CD. Have done some searching but to date have not found one.
 
> Then decided to try starting. Followed the connect green and black wires of main power connector http://www.instructables.com/id/Take-a-Look-Inside-a-ATX-power-supply-for-computer/ to start and was surprised that green lite on PSU came on and got readings of 11.89V for yellow and black, and 5.15V for red and black wires of a
parallel HDD connector.
 
> Am wondering if 11.89V for HDDs is too low? I do not have a scope to check the wave form but the readings were stable on my meter.
 
 
 
11.89 is fine for the 12 volt line.
KenO <kenitholson@yahoo.com>: Feb 17 10:05AM -0800

Hi,
 
Inherited an electronics unit that has severe contact corrosion due to bad alkaline batteries.
 
Appreciate any suggestions how to restore these contacts to working condition.
 
Thanks
 
Ken
John-Del <ohger1s@gmail.com>: Feb 17 11:58AM -0800

On Saturday, February 17, 2018 at 1:05:38 PM UTC-5, KenO wrote:
 
> Appreciate any suggestions how to restore these contacts to working condition.
 
> Thanks
 
> Ken
 
 
The first thing to try when removing battery snot is plain old water. If the plating is gone, you'll either have to replate or replace the contacts for reliable contact.
Reinhard Zwirner <reinhard.zwirner@t-online.de>: Feb 17 09:06PM +0100

John-Del schrieb:
>> Hi,
 
>> Inherited an electronics unit that has severe contact corrosion due to bad alkaline batteries.
 
>> Appreciate any suggestions how to restore these contacts to working condition.
 
As has been suggested in a previous thread: (concentrated) white vinegar.
 
HTH
 
Reinhard
"Ian Field" <gangprobing.alien1@virginmedia.com>: Feb 17 08:38PM

"KenO" <kenitholson@yahoo.com> wrote in message
news:0b5dd2ba-3e16-48b6-8eb3-6fefbf4e4f96@googlegroups.com...
 
> Appreciate any suggestions how to restore these contacts to working
> condition.
 
> Thanks
 
Dry corrosion/residue is best removed mechanically - once its clean enough
for reliable contact, give it a squirt of silicone spray.
 
Don't try rebuilding contact surfaces with solder, oxidisation makes
unreliable contact - sometimes its possible to graft on a strip of clean
metal - solder it on, but don't get any on the contact surface.
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Digest for sci.electronics.repair@googlegroups.com - 3 updates in 2 topics

philo <philo@privacy.net>: Feb 17 07:27AM -0600

The guy finally tested it and it did not do the job.
 
 
The good news is he was able to get a good, used unit locally.
 
 
So his shop has two working units.
 
 
On 02/05/2018 11:54 AM, philo wrote:
etpm@whidbey.com: Feb 16 09:33AM -0800

On Thu, 15 Feb 2018 11:54:27 -0800 (PST), KenO <kenitholson@yahoo.com>
wrote:
 
 
>Appreciate any help!
 
>Thanks
 
>Ken
 
Recently I had a power supply in a computer that was going bad. It
wouldn't work properly until it was warm. I replaced it but before I
did I found that directing the warm air from a blow dryer through the
fan and warming the power supply would allow it to turn on. Once on it
would stay on. The hair dryer was a good way to determine that it was
the power supply and not the computer itself that was the problem.
Advice from the folks on the group helped too.
Eric
Ralph Mowery <rmowery28146@earthlink.net>: Feb 16 12:43PM -0500

In article <g85e8dpepd11b6t68m1i120ps50tmcjdea@4ax.com>,
etpm@whidbey.com says...
> the power supply and not the computer itself that was the problem.
> Advice from the folks on the group helped too.
> Eric
 
Probably some bad capacitors in the supply.
 
I had a piece of equipment with a power supply that had lots of
capacitors in it. I found the bad ones by directing the hot air from my
hot air rework station at them. I may have replaced some that were ok,
but they are inexpensive compaired to a new supply. Actually can not
get a new one, but a company repaires them for about $ 150.
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